A Processing Scheme for Long Integration Time Passive Radar based on CZT and FRFD-Sharpness

In this paper a problem of extending integration time in passive radar is addressed. To compensate range and Doppler walk, a processing scheme based on chirp-z transform (CZT) and fractional Fourier transform domain (FRFD) sharpness is proposed: (1) divide the signal into snapshots; (2) perform Fourier transform (FT) and matched filtering on each snapshot; (3) perform CZT across the snapshots; (4) perform inverse FT (1FT) on each snapshot; (5) perform 1FT and fractional Fourier transform (FRFT) across the snapshots; (6) obtain the final radar image of moving targets by sharpness metrics. Experiment result by using DTV-based passive radar data has shown that the processing scheme can effectively mitigate range and Doppler walk, and it allows meaningful increases to the integration time.